"Aggro" is short for aggravate, instead of aggressive.
In short, aggressive is a state. An enemy is aggressive towards all players, but who they attack is determined by their level of aggravation towards the different members of the player group. Depending on the game, it can be affected by a number of factors such as DPS, abilities, or even healing allies.
Here are some sample sentences:
- "Don't aggro the boss until you clear the adds."
- Aggravate makes more sense than aggressive in this context.
- "Those enemies have a very large or small aggro radius."
- Aggravation works better than aggressive or aggression, because mobs that trigger based on range are considered "aggressive" already.
- "X DPS class out aggro'd the tank, that's what caused the wipe."
- It makes more sense that it means "X DPS caused the enemy more aggravation than the tank, thus causing the enemy to shift its focus."
